3
Half of a set
Learner’s Book 1: Unit 11, p. 161
GoalFind half of a group of objects by sharing equally into 2 groups.
New words
set · a group of thingsshare equally · give the same number to eachhalf of · one of 2 equal shares
Explanation
We can find half of a group of things, not just half of one object. Share the group equally between 2. Give one to the first, one to the second, and keep going until all are shared. Each group is half of the set. Half of 8 is 4, because 4 and 4 make 8. If one thing is left over, the group cannot be shared equally.
Worked examples
Half of 6 apples is 3. Two groups of 3 make 6.
Half of 12 stars is 6. Share them one by one: 6 for each group.
5 cherries cannot be shared equally between 2. Each gets 2 and 1 is left over.
Class activity
Sharing game: take 20 beans or buttons. Roll a dice and count out that many. Can you share them equally into 2 cups? If yes, say ‘half of … is …’. If one is left over, say ‘cannot share equally’. Which dice numbers always work?
Practice
1
Share these fish equally between 2 tanks. How many go in each tank?
5
2
Ali and Leo share these flowers equally. How many does each boy get?
8
3
What is half of 4?
2
4
Tom has 20 carrots. He gives half to his rabbits. How many carrots do the rabbits get?
10